1. Field of the Invention
The present invention relates to an image-pickup unit which is used for an image-taking apparatus such as a digital camera.
2. Description of the Related Art
In Japanese Patent Application Laid-Open No. 2002-218293, a method of mounting a solid image-pickup element on an image-taking apparatus such as a digital camera etc. by using a hollow TAB (tape automated bonding) package is disclosed. In this mounting method, a locating hole is provided in a TAB tape (flexible circuit board) which is located at and fixed to a structural member of a camera using the locating hole.
Further, the hollow TAB package is located at and held along an optical axis in such a manner that the structural member is in contact with the surface of the TAB tape toward an image-taking lens.
In addition, in Japanese Patent Application Laid-Open No. 2001-309244, a method of forming a metallic film on a cover glass is disclosed, in which metallic components provided in an apparatus such as a camera are connected to the metallic film of the cover glass by melting, cooling and hardening metallic material such as solder.
However, in a mounting method disclosed in Japanese Patent Application Laid-Open No. 2002-218293, since the TAB package is located and held at the optical axis by using the TAB tape, the following problems commonly occur.
The TAB tape may be easily bent, and further it may be deformed in a bending direction of the tape due to low rigidity. Therefore, if a force is applied to the TAB tape by the weight of the hollow TAB package or by a shock when dropped, the shape of the TAB tape typically deforms to change the location of a light-receiving surface of the image-pickup element.
Further, in the above mounting method, since the cover glass or the image-pickup element is bonded and fixed to the TAB tape, these components are held so as to be hanged by the TAB tape within a camera. Thus, if a force is applied to the cover glass or the image-pickup element, for example, by a shock when dropped, a bonding connection may be easily separated.
In addition, in the mounting method disclosed in Japanese Patent Application Laid-Open No. 2002-218293, a locating hole is provided in a first wiring portion (connecting portion) of the TAB tape for reading out signal from the image-pickup element. Accordingly, the connection between the first wiring portion of the TAB tape and another board wiring portion is made by bending a second wiring portion formed outside the locating hole of the TAB tape. Therefore, the wiring length of the second wiring portion of the TAB tape increases. Further, if the wiring length of the second wiring portion is increased, the signal from the image-pickup element is easily influenced by an external noise. Further, since the TAB tape has a longer length, the manufacturing cost increases. In addition, the size of an image-taking apparatus also increases inconveniently.
Meanwhile, in a mounting method suggested by Japanese Patent Application Laid-Open No. 2001-309244, since a high temperature melting solder is used, it causes the deformation of the cover glass or the image-pickup element due to a thermal stress when cooling.